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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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12/11/25

Message Overview:

Message Name:

[ACSC1-A] LH PACK INLET OVERHEAT

Message Code:

2161514ECS

Associated CAS:

L PACK FAIL
(Caution)

Reporting LRU: Air Conditioning System Controller (ACSC) 1
System Description: 21-51-00 - Filtering And Flow Control System
Schematic Diagram: 21-51-00 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wiring Diagram: 21-51-01 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Message Description:

A Pack Inlet Overheat condition has been detected by Air Conditioning System Controller (ACSC) 1A.

Possible Causes:

  • Air Conditioning System Controller 1 (A87)
  • Fan Air Valve (FAV) 1 (L22)
  • Fan Air Valve (FAV) Sense Line
  • Pneumatic Temperature Thermostat (THC) 1 (S8)
  • Pneumatic Temperature Thermostat (THC) Filter
  • Pack Inlet Flow Sensor 1 (MT66)
  • Pack Inlet Temperature Sensor 1 (E23)
  • Fan Air Duct
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None

Flight Operation Notifications Manual (FONM): None

Quick Links:

Removal of the Pack Inlet Flow-Sensors AMM 21-51-13-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Pack Inlet Flow-Sensors AMM 21-51-13-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Air-Conditioning System Controllers AMM 21-60-21-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Air-Conditioning System Controllers AMM 21-60-21-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Fan Air Valve AMM 36-11-17-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Fan Air Valve AMM 36-11-17-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Operational Test of the Fan Air Valve AMM 36-11-17-710-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Temperature Control Thermostat AMM 36-11-21-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Temperature Control Thermostat AMM 36-11-21-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Temperature Control Thermostat Filter AMM 36-11-21-000-802 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Temperature Control Thermostat Filter AMM 36-11-21-400-802 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wire Repair - Maintenance Practices - ALL SPM 20-12-10 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Troubleshooting Recommendations:

  1. Access System LRU Diagnostics with pack off and cold, verify if pack inlet temperature sensor and pack inlet flow sensor data is valid and compare with opposite side.

    1. If data is not valid, go to steps 8.
    2. If data is valid, continue with next step.

  2. Verify all sense lines for damage or leakage. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  3. Inspect Fan Air Valve sense line to pneumatic temperature thermostat (THC) for leaks. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  4. Remove the Pneumatic Temperature Thermostat Filter. Inspect for clogged filter. Clean/replace filter as required. Is the fault resolved?

    1. If YES, do close out.
    2. If NO, continue with next step.

  5. Perform operational test of the fan air valve.

    1. If test passes, do close out.
    2. If test fails, continue with next step.

  6. Interchange pneumatic temperature thermostat 1 with pneumatic temperature thermostat 2.

    1. If system checks are good, replace pneumatic temperature thermostat 1 and do close out.
    2. If fault remains, continue with next step.

  7. Inspect Fan Air Duct pre-cooler duct for leaks or obstructions. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  8. Interchange Fan Air Valve 1 with Fan Air Valve 2.

    1. If system checks are good, replace Fan Air Valve 1 and do close out.
    2. If fault remains, continue with next step.

  9. Interchange Pack Inlet Flow sensor 1 with Pack Inlet Flow sensor 2.

    1. If system checks are good, replace Pack Inlet Flow sensor 1 and do close out.
    2. If fault remains, continue with next step.

  10. Perform wiring checks between Pack Inlet Temperature sensor, Pack inlet flow sensor and ACSC 1.

    1. If wiring checks are not good, repair the defective associated wiring and do close out.
    2. If wiring checks are good, continue with next step.

  11. Replace Pack Inlet Temperature sensor 1.
  12. Do close out.

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